{"id":"CVE-2026-117601","aliases":[],"title":"Electrum before 4.8.3 Missing Signature Verification of Mempool Transactions","description":"Electrum before 4.8.3 fails to verify signatures of wallet-owned inputs in unconfirmed mempool transactions, allowing malicious servers to replace a just-broadcast transaction with a conflicting one. Attackers can swallow the user's transaction and display an invalid zero-fee copy paying an attacker address, tricking users into RBF fee-bumping and signing it.","severity":"critical","score":9.3,"published":"2026-10-27T13:09:51.347Z","modified":"2026-10-27T13:09:51.347Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://github.com/spesmilo/electrum/security/advisories/GHSA-6jp4-8v48-cc5v","https://github.com/spesmilo/electrum/commit/90fe30822561e515a9d2d6e5a352cc07780999eb","https://www.vulncheck.com/advisories/electrum-before-4.8.3-missing-signature-verification-of-mempool-transactions"],"sources":[{"name":"CVE","id":"CVE-2026-117601","modified":"2026-10-27T13:09:51.347Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-117601"}],"assessments":[{"source":"CNA","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","score":9.3},{"source":"CNA","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","score":7.5}]}